Earthworm's Species

Earthworm's Species

While earthworm taxonomists have identified thousands of individual worm species, only six have been identified as useful in vermicomposting systems to date. These species were evaluated based on their ability to tolerate a wide range of environmental conditions and fluctuations, handling and disruption to the worm bed, and for their growth and breeding rate. Earthworm species with a short generation time, meaning a relatively short life span and rapid growth and reproductive rate, have been identified as most effective due in large part to the high concentration of juvenile worms present in their populations. Juvenile worms, like human teenagers, are voracious consumers, keeping the processing rate of the system high and ensuring an ongoing succession of young worms.The growth and reproductive rates of each worm species listed below are the maximum identified under ideal conditions. These rates decline the further environmental conditions within the system shift from ideal.Please note the Latin name of each earthworm species. Common names can be very misleading and often vary between different regions of the world and even regions within a country. It is very difficult to be sure which species of worm is being discussed unless the Latin name is being used. Professional worm growers should know and use the Latin names of the worms they culture.

Eisenia fetida* / Eisenia andreii(common name, Red Worm)

There are two worm species listed here because in virtually all cultures of E. fetida, E. andreii is present. E. andreii so closely resembles E. fetida in behavior, environmental requirements, reproductive and growth rate, and appearance that the only way to distinguish between the two is through molecular scanning . There is no external difference between the two species. For all intents and purposes these worms can be considered identical. Eisenia fetida is generally the only worm mentioned because the two are so closely associated and because fetida is typically the more populous of the two.Eisenia fetida/Eisenia andreii are the worm species identified as the most useful in vermicomposting systems and are the easiest to grow in high-density culture because they tolerate the widest range of environmental conditions and fluctuations, and handling and disruption to their environment of all species identified for this purpose. E. fetida/E. andreii are also common to virtually every landmass on earth, meaning there is no concern over importing potentially alien species to an environment where they might cause damage.While this worm species is considered the premier worm for most applications, it is a small worm, not always suited for use as bait.* Temperature range: Minimum; 38° F, maximum; 88° F, ideal range; 70° F-80° F.* Reproductive rate: Approximately 10 young per worm per week under ideal conditions.* Average number of young per cocoon: Approximately 3.* Time to emergence from the cocoon: Approximately 30-75 days under ideal conditions.* Time to sexual maturity: Approximately 85-150 days under ideal conditions.*Note: The spelling ‘ fetida ' was changed a few years ago to ‘ foetida ' then subsequently changed back for reasons clear only to a few earthworm taxonomists. The different spellings do not denote different species. Information on this species can be found under both spellings, though the correct spelling is ‘ fetida '.

Eudrilus eugeniae(common name, African nightcrawler)

This worm is a semi-tropical species, meaning it cannot easily tolerate cool temperatures and is usually grown indoors or under temperature controlled conditions in most areas of North America. E. eugeniae is a large species, well suited for use as a bait worm, but does not tolerate handling or disruption to its environment.This species is used in some vermicomposting systems around the Mediterranean region and in some areas of eastern Asia.* Temperature range: Minimum; 45° F, maximum; 90° F, ideal range; 70° F-80° F.* Reproductive rate: Approximately 7 young per worm per week under ideal conditions.* Average number of young per cocoon: Approximately 2.* Time to emergence from the cocoon: Approximately 15-30 days under ideal conditions.* Time to sexual maturity: Approximately 30-95 days under ideal conditions.

Amynthas gracilus(common name, Alabama or Georgia jumper)

A. gracilus is another large worm species well suited for use as bait. It is also a tropical species with a poor tolerance for cold temperatures. This worm tolerates handling and disruption to the worm bed as well as does E. fetida and is generally considered an easy worm to culture provided appropriate temperatures can be maintained.A. gracilus is used in a few vermicomposting systems in Malaysia and the Philippines.* Temperature range: Minimum; 45° F, maximum; 90° F, ideal range; 70° F-80° F.* Reproductive rate: Undetermined, though believed to be similar to E. eugeniae.* Average number of young per cocoon: Undetermined, though believed to be similar to E. eugeniae .* Time to emergence from the cocoon: Undetermined, though believed to be similar to E. eugeniae* Time to sexual maturity: Undetermined, though believed to be similar to E. eugeniae

Perionyx excavatus(common name, Indian Blue worm)

Perionyx excavatus is a beautiful worm with an iridescent blue or violet sheen to its skin clearly visible under bright light. It is a very small worm, poorly suited as fishing bait, but has an impressive growth and reproductive rate far in excess of the other species grown in bin culture.This is another tropical worm species with a very poor tolerance for low temperatures, fluctuations in the bin environment, handling or disruption to the system. P. excavatus is often referred to as “the Traveler” for its tendency to leave the bin en masse for no apparent reason.Due to it's temperamental nature this species is rarely used in vermicomposting systems in North America, though it is naturally occurring at low population levels in systems in contact with the soil in the southeastern US and most tropical regions of the world.* Temperature range: Minimum; 45° F, maximum; 90° F, ideal range; 70° F-80° F.* Reproductive rate: Approximately 19 young per worm per week under ideal conditions.* Average number of young per cocoon: Approximately 1.* Time to emergence from the cocoon: Approximately 15-21 days under ideal conditions.*Time to sexual maturity: Approximately 30-55 days under ideal conditions.

Eisenia hortensis(European nightcrawler)

E. hortensis is a large worm species well suited for use as a bait worm. Its ideal temperature range is a bit cooler than is that of E. fetida and it requires higher moisture levels than do the other species tested for use in bin culture and vermicomposting, but the species tolerates handling and disruption to its environment, and environmental fluctuations very well.Because this worm has a very low reproductive and growth rate, relatively speaking, it is considered the least desirable species of those tested for either bin culture or vermicomposting systems. It is used in a few vermiprocessing systems in Europe for the remediation of very wet organic materials.* Temperature range: Minimum; 45° F, maximum; 85° F, ideal range; 55° F-65° F.* Reproductive rate: Just under 2 young per worm per week under ideal conditions.* Average number of young per cocoon: Approximately 1.* Time to emergence from the cocoon: Approximately 40-125 days under ideal conditions.* Time to sexual maturity: Approximately 55-85 days under ideal conditions.For the scientific mind here's some useful data:A Series of Searchable Texts on Earthworm Biodiversity, Ecology and Systematics from Various Regions of the WorldTHE FORMATION OF VEGETABLE MOULD THROUGH THE ACTION OF WORMS WITH OBSERVATIONS ON THEIR HABITS.by Charles Darwin 1809-1882[FIRST EDITION, October 10th, 1881.] ~Source Gutenberg's Project